ST. LOUIS, MO - NOVEMBER 24: Head Coach Marc Trestman of the Chicago Bears watches from the sidelines during a game against the St. Louis Rams at the Edward Jones Dome on November 24, 2013 in St. Louis, Missouri. (Photo by Michael Thomas/Getty Images)Marc Trestman. (Michael Thomas/Getty Images)

By Steve Silverman-

(CBS) Marc Trestman is under the gun this week.

It’s one thing to be an offensive guru and the quarterback whisperer. The Bears’ offense was largely inefficient and lacked creativity in the Lovie Smith era, and general manager Phil Emery brought in Trestman to turn that around.

He has done that rather brilliantly. The offense has reached new levels, whether Jay Cutler or Josh McCown have lined up under center. Alshon Jeffery has developed into a Pro Bowl receiver. Tight end Martellus Bennett is not a Pro Bowl player, but he catches nearly everything he touches.

Brandon Marshall and Matt Forte were already high-level performers, and there has not been any slippage.

While there have been a few exceptions – especially Sunday night against the Eagles – the Bears’ offense has reached the levels that were expected. They rank eighth in yards per game, fifth in passing yards per game and third in points per game.

That last figure – 27.8 ppg – is probably the most important of the three.

But this week Trestman must show exactly what kind of old-school football coach he is. He has to prepare his entire team and get his players ready for their peak effort of the season.

Motivation is the word.

Trestman is not a yeller or a screamer. He does not seem to have the same kind of make-up of classic football coaches of the past. Bill Parcells, Jimmy Johnson and Don Shula would not hesitate to turn up the volume and threaten jobs.

Trestman does not operate that way.

Trestman has to motivate his team this week, especially after the 54-11 debacle against the Eagles. The NFL may be a league where the outcome from week-to-week leaves observers scratching their heads, but teams don’t turn it around just by happenstance. Coaches figure out what went wrong and then repair those issues.

The Green Bay Packers represent a major psychological hurdle. While the Bears defeated the Packers 27-20 in early November, Green Bay had beaten the Bears in their six previous meetings.

They have confidence against the Bears. Of course, a large part of that confidence stems from having Aaron Rodgers in the lineup. Rodgers has not made it back under center since he fractured his left collarbone against the Bears, and there are no guarantees he will make it back in for this game.

The initial thought that Rodgers would be ready to play by Thanksgiving seemed pie-in-the-sky, but it’s surprising that he has not made it back into the lineup by late December.

With every passing week, Mike McCarthy has dutifully told the press about “the organizational decision” to keep Rodgers on the sideline. There is a fear in Green Bay that Rodgers would have been back by now and that the “organization” is going to shut him down for the year. We shall see.

Rookie running back Eddie Lacy’s ankle is also a huge issue, because the Packers finally have a ground game this year. Lacy has rushed for 1,112 yards and 10 touchdowns, and has the kind of bruising style that would allow him to pick up huge chunks against the Bears’ 32nd-ranked run defense.

But Lacy’s ankle may limit him or prevent him from playing. Backup James Starks was aggressive and powerful vs. the Steelers last Sunday, and he is averaging 5.2 yards per carry, which is a full yard better than Lacy.

Finally, linebacker Clay Matthews broke his thumb again and he will not play. He is one of the emotional leaders of the team and without his ability to create momentum changing plays, the Packers will suffer.

But there are no questions that Green Bay head coach Mike McCarthy will get his team – or what’s left of it – prepared and ready to play. He has done this many times in the past, especially against the Bears.

Trestman has to show he is capable of preparing his team for a peak effort. He must first get the Bears to erase the loss at Philadelphia from their collective memories and then move forward. He must find a way to get his team to believe in itself and play its best game when it matters most.

There is nothing about Trestman that is old-school in his approach. He’s going to have figure out his own way how to do this, because nothing else that will suffice.